1. Technical Field
The present invention relates to a liquid container that supplies liquid retained in a liquid container body thereof to a liquid consumption apparatus.
2. Related Art
An ink cartridge containing ink inside thereof and an ink-jet recording apparatus to which such an ink cartridge is attached as a removable unit is a well known example set of a liquid container and a liquid consumption apparatus.
Inside the container body thereof which is detachably attached to the cartridge attachment unit of an ink-jet recording apparatus, a known ink cartridge has as its typical configuration ink-containing chambers (i.e., rooms or compartments) in which ink is retained, an ink supply port that is provided to supply the ink retained in the ink-containing chambers to the ink-jet recording apparatus, and an ink flow channel through which the ink-containing chambers communicate with the ink supply port. Such a known ink cartridge is configured to supply ink retained therein to the ink-jet recording apparatus through an ink supply needle that is provided on the cartridge attachment unit of the ink-jet recording apparatus when the ink cartridge is attached to the cartridge attachment unit thereof in such a manner that the ink supply needle of the cartridge attachment unit is inserted through the ink supply port of the ink cartridge.
Generally speaking, air bubbles often form in ink retained in an ink cartridge due to a temperature change during long-term storage, vibrations generated during shipping, or some other reason. These air bubbles deteriorate the ink-supply characteristics of the affected ink cartridge that is attached to an ink-jet recording apparatus, which could result in poor print quality. In order to suppress the forming of air bubbles inside an ink cartridge, as a known technique, an ink cartridge is vacuum packed immediately after its production so as to seal the periphery of the container body thereof as a pressure-reduced space. As a further technical insurance for prolonged storage, JP-A-2000-33709 proposes a technique to prolong the efficacy of reduced pressure in a vacuum-packed ink cartridge for a long time. Specifically, it is described in the above-identified publication that a concave portion, which is formed in the outer surface of the top cover of the container body of an ink cartridge that has ink-containing chambers, is utilized as a deaeration chamber, that is, a space into which any remaining air can be expelled, which contains/accumulates negative pressure for deaeration when the ink cartridge is subjected to vacuum packing.
In order to prevent the recording head of an ink-jet recording apparatus from performing “empty-cartridge printing” after the attached ink cartridge has run out of ink retained therein, some of ink-jet recording apparatuses have an ink remaining amount detection sensor that outputs a predetermined electric signal when the remaining amount of ink retained in the container body thereof reaches a certain predefined threshold. As described in JP-A-2001-146019, some of recently developed ink cartridges are provided with such an ink remaining amount detection sensor that is made up of a cavity that forms a part of an ink flow channel, a diaphragm that constitutes a part of the wall surface of the cavity, and a piezoelectric element that is provided on the diaphragm. In this type of recent ink cartridge, the remaining amount of ink is detected on the basis of a change in residual vibration in response to a vibration applied to the diaphragm.
Very small air bubbles could sometimes form (and remain) when, for example, ink is filled at a factory in the ink-containing chambers inside the container body during a production process of an ink cartridge. Disadvantageously, in an ink cartridge of related art that is provided with an ink remaining amount detection sensor, there is no way to remove air bubbles that formed at the time of filling of ink. Therefore, the air bubbles could remain in the cavity of the ink remaining amount detection sensor. If any air bubbles remain, there is a possibility that an erroneous detection of an ink-absent state could occur although there is still a sufficient amount of ink left inside at the time of starting the use of the ink cartridge. This erroneous detection occurs because the remaining air bubbles affect residual vibration.